What has been published:
A. Postmortem studies (microscopic and biochemical) have demonstrated that infants who die of SIDS, as a group, have a chronic abnormality which involves the brain stem.
B. Neonatal observations on subsequent SIDS victims (compared to controls) revealed group differences in reflexes, feeding behavior, unusual cries and an increased amount of brief apneic pauses during feeding and sleep.
C. A number of literature reviews have concluded that there is sufficient evidence to draw the general conclusion that, as a group, infants who die of SIDS have a subtle chronic abnormality that existed within the first few days of life.
D. Postmortem studies have demonstrated that respiratory failure or respiratory difficulty heralds the terminal event.
E. Postmortem studies have demonstrated that, as a group, SIDS victims had a number of apneic episodes prior to the terminal event.
F. Infants resuscitated following an apparent life threatening event (an episode of apnea or respiratory difficulty that was frightening to a parent) are at increased risk to die of SIDS.
G. Reviewers have concluded that there was no scientifically valid method for identifying infants at risk for SIDS or prolonged apnea.
H. Multi-channel recordings during sleep have become a standard in diagnosing sleep disorder and sleep apnea in adults.
I. In a published study (1978), infants who had prolonged apnea also had an increased frequency and duration of brief apneic pauses (statistically significant) when studied during sleep in a manner similar to that described in "How to test." It was during this study that the PSA4 and A6/D measures were developed.
J. A study demonstrated that 50% of infants who died of SIDS (N=10) had abnormal test scores (PSA4 or A6/D %) during a sleep or feeding evaluation conducted within the first week of life. These results were statistically significant.
K. In a prospective study supported by a research grant from the National Institute of Child Health and Human Development, a large number of normal infants born at the University of Maryland Hospital (Baltimore, Md.) were studied within the first and fourth week of life using most of the techniques described earlier. These data provided the basis, in part, for developing statistical norms. A newly developed apnea/bradycardia monitor (with an attached recorder) was made available for use by those whose sleep study was abnormal. Although the sample size was not totally adequate, a pilot study was conducted in which the SIDS rate was determined for those babies born at the University of Maryland Hospital prior to and during the conduct of the primary project and compared to comparable data for babies born at Johns Hopkins Hospital. The hypotheses examined were that: a) home monitoring and early resuscitative intervention will reduce the incidence of SIDS and b) the physiologic studies will identify infants at high risk. The results obtained were consistent with these hypotheses.
It is an object of the present invention to provide an improved method for predicting the liklihood an infant will be a risk for prolonged apnea.